Propylene glycol is a clear, odorless liquid often (but not always) derived from petroleum.
You can find propylene glycol everywhere–from antifreeze to salad dressings and so much more. In skincare, however, it serves three main purposes. First, it’s used as a humectant (which means it draws moisture to the surface of your skin). Second, it’s an emulsifier (which helps keep your product from separating). Third, it’s a used as a solvent (which means it can dissolve other ingredients).
I know what you’re thinking–propylene glycol is derived from petroleum, so it must be bad. But, that’s not the case. It’s used widely because of its low toxicity. One study subjected 20 people to propylene glycol aerosols for a little over 4 hours. They observed that the aerosols did not affect respiratory health.
Another assessment found propylene glycol to be non-toxic, non-carcinogenic, and otherwise safe to use in cosmetics as long as it’s formulated correctly.
Even though it doesn’t pose a threat to most people, there’s always a chance you can be allergic to it. So, as always, patch testing is imperative. Contact dermatitis has been reported by many allergic patients.
Another thing to consider is that there’s limited research on how propylene glycol can affect pregnant women and babies. Although comprehensive research found that propylene glycol doesn’t have any negative short-term effects on newborns, I didn’t find anything that measured long-term effects.
- Methylethylene glycol
- 1,2 propanediol
- Dipropylene Glycol
- Tripropylene Glycol
What It’s Used In
Cosmetics, Fragrances, Medications, Deodorants, Mouthwash, Antifreeze, E-Cigarettes, Paints, Frozen foods, Salad dressings, Inks, De-icing agents (for airplanes), and a lot of other things
Yes, it’s a main ingredient in antifreeze and e-cigarettes. But, in small doses, it’s fairly non-toxic.